The field of art to which this invention pertains is spun yarn. The invention is more specifically directed to a process for making such yarn from a three-component blend of staple fibers using high speed, air spinning techniques with spinning speeds in excess of 70 meters per minute. In a preferred embodiment these speeds can range from 150 to 220 meters per minute.
The fiber blend used in the process is formed from a plurality of selected filaments. One component of the blend comprises staple fibers made from filaments having an electrically conductive carbon black core and a sheath of non-conductive polymer. The other two components, which are heat-resistant, are preferably formed from filaments of poly(m-phenylene isophthalamide) and of poly(p-phenylene terephthalamide).
The deniers of the electrically conductive sheath core filaments are preferably no greater than 2.5 times the deniers of the other filaments. This helps prevent or lessens their migration to the surface of the spun yarn during the spinning operation and thereby improves the appearance of the yarn and of the fabrics woven from such yarn.